US6046962A - Electrodynamic transducer for underwater acoustics - Google Patents

Electrodynamic transducer for underwater acoustics Download PDF

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Publication number
US6046962A
US6046962A US09/084,741 US8474198A US6046962A US 6046962 A US6046962 A US 6046962A US 8474198 A US8474198 A US 8474198A US 6046962 A US6046962 A US 6046962A
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US
United States
Prior art keywords
transducer according
transducer
mobile structure
horn
dome
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US09/084,741
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English (en)
Inventor
Vito Suppa
Jean Bertheas
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Thales Underwater Systems SAS
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Thales Underwater Systems SAS
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Assigned to THOMSON MARCONI SONAR SAS reassignment THOMSON MARCONI SONAR SAS ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: BERTHEAS, JEAN, SUPPA, VITO
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    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/004—Mounting transducers, e.g. provided with mechanical moving or orienting device
    • G10K11/006—Transducer mounting in underwater equipment, e.g. sonobuoys
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
    • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
    • B06B1/04—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with electromagnetism
    • B06B1/045—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with electromagnetism using vibrating magnet, armature or coil system

Definitions

  • the present invention relates to electrodynamic type transducers that enable the transmission, within the sea, of acoustic waves and more particularly sound waves. These transducers are particularly useful in sonar technology.
  • the transducer To be able to obtain the acoustic power frequently needed in certain applications, given the acoustic level to be attained which can be as much as 150 dB at 10 Hz, it becomes necessary to use relatively large-sized transducers. This leads to constraints, in volume as well as in weight, because the transducer has to be immersed in the sea while being placed in a fish that has to navigate at a predetermined depth of immersion.
  • the transducer often needs to be capable of withstanding the explosions that may sometimes occur in particular applications.
  • the effect of an underwater explosion of this kind results in the application, to the transducer; of a level of hydrostatic pressure and acceleration. This level of hydrostatic pressure and acceleration is easily destructive at the horn and at the tight-sealing membrane between the horn and the transducer pack.
  • a dome drilled with holes is placed over the horn of such a transducer, and the dome itself is covered with a membrane.
  • Each of the holes thus forms a valve that lets through the vibrations corresponding to the acoustic signals emitted by the transducer, and does not let through the peaks of pressure that come from explosions if any.
  • Such a system however has the disadvantage of increasing the volume and the mass of the transducer, and of decreasing the level of sound that it can deliver.
  • an electrodynamic transducer for underwater acoustics, of the type comprising a body fitted with pole pieces defining a gap, a mobile structure fitted with a dome extended by a cylinder supporting a coil that slides in this gap, and a flexible membrane that provides tight sealing between the mobile structure and the body, wherein chiefly said transducer further comprises a horn surmounting said dome and sliding in said body by forming an adjutage with said body, the value of whose play is fixed so as to enable the protection of said membrane against the shock waves coming from explosions external to the transducer by flattening these shock waves in said adjutage.
  • the mobile structure further comprises a set of radial ribs fixed on one side to the interior wall of this mobile structure and joined together on the other side in a star arrangement to increase the stiffness of this mobile structure and its resistance to said shock wave.
  • the transducer further comprises a spring fixed at its periphery to the lower part of the body and connected at its center to the center of the star formed by the meeting of said ribs, this spring enabling the mobile structure to be centered along the vertical axis.
  • the transducer further comprises a peripheral cavity made in the body and connected to the external environment by at least one perforation and a toroidal, elastic air chamber contained in this peripheral cavity connected to the lower cavity defined by the body and the mobile structure to compensate for the effects of the hydrostatic pressure due to the immersion; the difference in height between the horn and this air chamber enabling the mobile structure to be maintained in a neutral position.
  • FIG. 1 shows a vertical cross-section of half of a transducer according to the invention.
  • FIG. 2 shows a horizontal view along the plane AA of the transducer of FIG. 1.
  • the transducer according to the invention shown in the two appended figures comprises a body formed by a base 101 into which there is fixed a jacket 102 surmounted by a cup 103. These different parts are fitted into one another so as to demarcate cylindrical cavities with a shape generated by revolution around the axis of the transducer, and the other parts forming this transducer get inserted into these cylindrical cavities.
  • a first cylindrical cavity demarcated between the base and the jacket makes it possible to maintain a magnetic circuit formed by a first pole piece and a second pole piece, 104 and 105, in the shape of crowns centered on the axis of the transducer.
  • the first pole piece 104 is L-shaped with the inner arm of the L extending into the central chamber of the transducer.
  • the second pole piece 105 has the shape of a flat washer or disc. Both are kept separate by a set of magnets 106 to which they are clamped by the adjustment of the jacket 102 in the base 101.
  • the central space of the body of the transducer forms a second cylindrical cavity in which a mushroom-shaped core 108 gets embedded by its central stem in the central circular aperture of the pole piece 104.
  • the lower part of the head of the core which has an appreciably hemispherical shape, rests on the upper part of this same pole piece 104.
  • the mobile structure of the transducer is formed by a hollow part 109 having the shape of a dome capping a cylindrical part that gets engaged in the gap 107.
  • this part may be very solid, very light and very rigid all at the same time, it is formed for example by a carbon fibre fabric embedded in a resin matrix.
  • the upper surface of the dome 109 is covered with a part 110 whose upper surface is appreciably flat.
  • This part 110 forms the radiating horn of the transducer. So that it may be very light, it is made for example out of syntactic foam.
  • the horn 110 thus behaves like a piston whose lateral external surface is cylindrical.
  • This piston slides in a cylinder formed by the lateral internal surface of the cup 103, which is itself appreciably cylindrical.
  • these two parts, and more particularly the horn 110 are made so as to have an extremely tight-fitting clearance of about 0.2 mm for example.
  • a mechanical filter is formed. This mechanical filter slows down the propagation of the shock wave that could arise out of an external explosion if any by flattening, in this interstice, the fluid in which the horn bathes.
  • the upper part of the central space of the body of the transducer is filled, a known way, with a fluid, an oil for example, suited both to this protection and to the propagation of the acoustic waves.
  • a fluid an oil for example, suited both to this protection and to the propagation of the acoustic waves.
  • the space 113 is closed at its upper part by a membrane 112 fixed to the rim of the cup 103.
  • the lower part of the central space, opposite the part in which this oil is located, is for its part filled with air.
  • another tight-sealing membrane 115 is used.
  • This tight-sealing membrane is made of rubber for example. It is much more flexible than the membrane 112 and is fixed, on the one hand, to the external lateral wall of the horn 110 and on the other hand on the interior side wall of the cup 103. In this exemplary embodiment, this fixing is obtained by clamping between this cup 103 and the jacket 102.
  • the external side surface of the horn is machined on this level so as to be recessed with respect to the adjutage 111 with the reduced clearance described here above, and so as to form an unoccupied space for the membrane 115.
  • the invention proposes to stiffen this assembly by using a set of radial ribs 116 that are distributed on the inner periphery of the dome 109 and meet in a star arrangement below the lower part of the stem of the mushroom forming the core 108. These ribs slide in grooves 117 made in the core 116 and the first pole piece 104. These grooves are relatively broad at the core and are narrower at the pole piece to minimize the loss of magnetic flux, which can be reduced to a very low value of a few percent.
  • An shaft 118 joins the center of the upper part of the dome 109 to the center of the star formed by the meeting of the ribs 116, below the lower face of the core 108.
  • This shaft makes it possible to stiffen the assembly and, at the same time, to ensure its vertical centering in relation to the axis of the transducer.
  • the shaft is fixed by its lower part to the center of a leaf spring 119 that is itself fixed circumferentially in the lower part of the base 101.
  • This spring of the type known as a ⁇ flector>>, is formed by a flexible and elastic disc with circumferential apertures that let air pass freely into the lower part of the central space of the transducer, between the two parts demarcated by the plane of this spring. This spring not only ensures the centering but also prevents rotational movements in the mobile structure that make the ribs rub against the walls of the grooves in which they slide.
  • the driving action which makes it possible to move the domehorn unit along the axis of the transducer, to emit acoustic waves, is obtained by the interaction between the magnetic field that circulates between the pole pieces and the magnetic field delivered by a coil 120 wound on the lateral flanks of the lower cylindrical part of the dome 109. This coil is thus plunged in the gap existing between the two pole pieces.
  • This coil is fed by means that are not shown on the figure and are known in the prior art.
  • the ribs 116 also serve as a heat sink all along the height of the coil 120, to dissipate the heat released at this level in directing it towards the other parts of the transducer.
  • the internal part 114 demarcated by the dome 109, the base 101 whose bottom is closed, the jacket 102 and the tight-sealing membrane 115 is filled with air to allow the play of the mobile structure, as was seen further above.
  • the mobile structure When the transducer is immersed, the mobile structure, under the effect of the hydrostatic pressure, plunges towards the bottom of the base 101 by compressing the spring 119 and the volume of air included in this part 114. This motion naturally tends to modify the electroacoustic characteristics of the transducer, in particular by modifying the respective positions of the coil and of the pole pieces.
  • a compensation reservoir or air chamber 121 is used.
  • This air chamber 121 is formed by a flexible pocket, made of rubber for example, subjected to the pressure of the marine environment and communicating with the part 114 by means of a conduit 122.
  • this air chamber to protect this air chamber against the effect of possible explosions occurring in the marine environment, it has a toroidal shape and is located in another internal cylindrical cavity 123 that is demarcated within the transducer by the walls of the jacket 102 and the cup 103. This cavity is thus itself toroidal and closed, and it surrounds the site of the horn 110.
  • small apertures 124 are made in the lateral external wall of the jacket 102. These apertures 124 allow sea water to penetrate the cavity 123 and compress the air chamber. In this way, the air chamber is protected against external mechanical aggression by the walls of the cavity in which it is located. Moreover the diameter of the apertures 124 is designed so that the shock waves coming from any external explosion are attenuated when passing through these apertures, so that they do not present any danger of excess pressure in the air chamber. Since these apertures are round, their diameter can be greater than the thickness of the adjutage 111.
  • transducers of this type are generally designed to function so as to emit the acoustic waves downwards, hence in the reverse position to the one shown in FIG. 1, the movement of the mobile structure towards the bottom of the body 101 under the effect of the hydrostatic pressure is then opposed simultaneously by the action of the spring 119, the action of gravity on the entire mobile structure, and the action of the hydrostatic pressure on the air chamber 121.
  • the invention proposes to set the dimensions of these various parts in such a way that there is a difference ⁇ H between the plane of the external surface of the horn and the average position of the air chamber; this distance being such that the difference in hydrostatic pressure between this surface and the air chamber, due to the difference between the immersions, balances the weight of the mobile structure.
  • This formula makes it possible, for a given construction, to obtain the maximum value of the immersion, and for a maximum value of desired immersion, to obtain the value of the volume of the air chamber, and hence the setting of its dimensions as well as those of the parts containing it.
  • a transducer having to be immersed with a 30 m depth must have an air chamber whose volume is appreciably equal to 3 times the volume of air in the remainder of the transducer.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Electromagnetism (AREA)
  • Mechanical Engineering (AREA)
  • Transducers For Ultrasonic Waves (AREA)
  • Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
US09/084,741 1997-05-27 1998-05-27 Electrodynamic transducer for underwater acoustics Expired - Lifetime US6046962A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9706457A FR2764160B1 (fr) 1997-05-27 1997-05-27 Transducteur electrodynamique pour acoustique sous-marine
FR9706457 1997-05-27

Publications (1)

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US6046962A true US6046962A (en) 2000-04-04

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US09/084,741 Expired - Lifetime US6046962A (en) 1997-05-27 1998-05-27 Electrodynamic transducer for underwater acoustics

Country Status (4)

Country Link
US (1) US6046962A (de)
EP (1) EP0881001B1 (de)
DE (1) DE69825361T2 (de)
FR (1) FR2764160B1 (de)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6345014B1 (en) 1998-03-10 2002-02-05 Thomson Marconi Sonar S.A.S. Collapsible annular acoustic transmission antenna
US6483778B1 (en) * 1999-04-02 2002-11-19 Raytheon Company Systems and methods for passively compensating transducers
US6515940B2 (en) 2000-05-26 2003-02-04 Thales Electrodynamic transducer for underwater acoustics
US6617765B1 (en) 1999-10-22 2003-09-09 Thales Underwater Systems S.A.S. Underwater broadband acoustic transducer
US20130051180A1 (en) * 2011-08-24 2013-02-28 Stephen Chelminski Marine vibratory sound source for beneath water seismic exploration
US10379207B2 (en) * 2013-12-20 2019-08-13 Thales Compact omnidirectional antenna for dipping sonar

Citations (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2545961A (en) * 1946-04-11 1951-03-20 Univ Loudspeakers Inc Reflex type loud-speaker
US3435407A (en) * 1965-06-29 1969-03-25 Csf High speed system for processing long range sonar pulses
US3639695A (en) * 1968-02-05 1972-02-01 Thomson Csf Systems for processing frequency modulated signals
US3745956A (en) * 1970-05-29 1973-07-17 Thomson Csf Self-guidance methods and devices for anti-submarine missiles
US3761821A (en) * 1970-10-16 1973-09-25 Thomson Csf Systems for processing and generating frequency modulated signals
US3835448A (en) * 1972-05-10 1974-09-10 Thomson Csf Multibeam steering system for a circular section acoustic transducer array
US4029141A (en) * 1974-12-17 1977-06-14 Thomson-Csf Cooling device for components which dissipate large amounts of heat
US4279025A (en) * 1978-07-18 1981-07-14 Thomson-Csf Releasable airborne buoy
US4295211A (en) * 1979-02-27 1981-10-13 Thomson-Csf Inertially released jettisonable airborne buoy
US4380440A (en) * 1979-08-28 1983-04-19 Thomson-Csf Droppable airborne buoy
CA1161895A (en) * 1981-10-21 1984-02-07 Garfield W. Mcmahon Moving coil linear actuator
US4466083A (en) * 1983-05-31 1984-08-14 The United States Of America As Represented By The Secretary Of The Navy Low frequency, broadband, underwater sound transducer
US4480322A (en) * 1981-04-15 1984-10-30 Thomson Csf Passive underwater range measurement acoustic system
US5058082A (en) * 1989-09-08 1991-10-15 Thomson-Csf Linear hydrophonic antenna and electronic device to remove right/left ambiguity, associated with this antenna
US5062089A (en) * 1987-04-17 1991-10-29 Argotec Inc. Sonar projector with liquid mass loading for operation at lower frequency

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6180996A (ja) * 1984-09-28 1986-04-24 Hitachi Ltd 水中送波器

Patent Citations (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2545961A (en) * 1946-04-11 1951-03-20 Univ Loudspeakers Inc Reflex type loud-speaker
US3435407A (en) * 1965-06-29 1969-03-25 Csf High speed system for processing long range sonar pulses
US3639695A (en) * 1968-02-05 1972-02-01 Thomson Csf Systems for processing frequency modulated signals
US3745956A (en) * 1970-05-29 1973-07-17 Thomson Csf Self-guidance methods and devices for anti-submarine missiles
US3761821A (en) * 1970-10-16 1973-09-25 Thomson Csf Systems for processing and generating frequency modulated signals
US3835448A (en) * 1972-05-10 1974-09-10 Thomson Csf Multibeam steering system for a circular section acoustic transducer array
US4029141A (en) * 1974-12-17 1977-06-14 Thomson-Csf Cooling device for components which dissipate large amounts of heat
US4279025A (en) * 1978-07-18 1981-07-14 Thomson-Csf Releasable airborne buoy
US4295211A (en) * 1979-02-27 1981-10-13 Thomson-Csf Inertially released jettisonable airborne buoy
US4380440A (en) * 1979-08-28 1983-04-19 Thomson-Csf Droppable airborne buoy
US4480322A (en) * 1981-04-15 1984-10-30 Thomson Csf Passive underwater range measurement acoustic system
CA1161895A (en) * 1981-10-21 1984-02-07 Garfield W. Mcmahon Moving coil linear actuator
US4466083A (en) * 1983-05-31 1984-08-14 The United States Of America As Represented By The Secretary Of The Navy Low frequency, broadband, underwater sound transducer
US5062089A (en) * 1987-04-17 1991-10-29 Argotec Inc. Sonar projector with liquid mass loading for operation at lower frequency
US5058082A (en) * 1989-09-08 1991-10-15 Thomson-Csf Linear hydrophonic antenna and electronic device to remove right/left ambiguity, associated with this antenna

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6345014B1 (en) 1998-03-10 2002-02-05 Thomson Marconi Sonar S.A.S. Collapsible annular acoustic transmission antenna
US6483778B1 (en) * 1999-04-02 2002-11-19 Raytheon Company Systems and methods for passively compensating transducers
US6617765B1 (en) 1999-10-22 2003-09-09 Thales Underwater Systems S.A.S. Underwater broadband acoustic transducer
US6515940B2 (en) 2000-05-26 2003-02-04 Thales Electrodynamic transducer for underwater acoustics
US20130051180A1 (en) * 2011-08-24 2013-02-28 Stephen Chelminski Marine vibratory sound source for beneath water seismic exploration
US8570835B2 (en) * 2011-08-24 2013-10-29 Stephen Chelminski Marine vibratory sound source for beneath water seismic exploration
US10379207B2 (en) * 2013-12-20 2019-08-13 Thales Compact omnidirectional antenna for dipping sonar

Also Published As

Publication number Publication date
FR2764160B1 (fr) 1999-08-27
EP0881001B1 (de) 2004-08-04
FR2764160A1 (fr) 1998-12-04
DE69825361T2 (de) 2005-08-11
DE69825361D1 (de) 2004-09-09
EP0881001A1 (de) 1998-12-02

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